Australia: Have you ever heard of nugget-producing bacteria? Chances are, they hold the key to more efficient processing of gold ore, mine tailings and recycled electronics, reveals the University of Adelaide in Australia.

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For over a decade, University of Adelaide researchers have been investigating the role of microorganisms in gold transformation.

In the natural environment, bacteria can dissolve and re-concentrate gold – this process removes most of the silver and forms gold nuggets.

The Australian researchers analysed numerous gold grains collected from West Coast Creek using high-resolution electron-microscopy. They report that that five so-called “episodes” of gold biogeochemical cycling had occurred on each gold grain.

‘Each episode was estimated to take between 3.5 and 11.7 years – a total of under 18 to almost 60 years to form the secondary gold,’ it is explained. ‘That’s a blink of an eye in terms of geological time,’ exclaims Dr Frank Reith.

‘These results have surprised us, and lead the way for many interesting applications such as optimising the processes for gold extraction from ore and re-processing old tailings or recycled electronics, which isn’t currently economically viable,’ he remarks.

‘If we can make this process faster, then the potential for re-processing tailings and improving ore-processing would be game-changing,’ confirms Dr Jeremiah Shuster. ‘Initial attempts to speed up these reactions are looking promising.’